A BRIDGE is a networking device that will connect numerous LANs (Local Area Networks) for forming a larger LAN. Also, it can connect LAN segments to form newer LAN segments. It operates in the OSI MODEL’s Data-Link layer. Bridges are helpful in increasing the network capacity of a single LAN by joining multiple LANs.

Working of Bridge:

The bridge will connect two or more different LANs that are having similar protocols and help to communicate between the devices (nodes) in them. It will accept all the data packets and all of them will be amplified to the other side. The bridges are considered to be intelligent devices as they will permit the passing of only selective packets from them.

A bridge will pass only those packets which are addressed from the node of one network to the node of the other network. That means the bridge will consult a database on receiving the data frame for DECIDING whether to pass, transmit or discard the frame.

• If the frame consists of a destination MAC (Media Access Control) address within the same network, then the bridge will pass the frame to that node and discard it later.
• If the frame consists of a destination MAC address within the connected network, then the bridge will forward the frame towards it.

Uses of Bridge:

• The capacity of the network will be INCREASED and multiplied as multiple smaller networks are combined to form a single network using the bridge.
• The database in the bridge will help for deciding whether a data frame should be transmitted or discarded on receiving the data frame.
• A single FAULTY node will be prevented from bringing down the whole network, by deciding on whether to forward or discard the data frame.
• It helps for frame broadcasting to each node even if the MAC or destination address is not available.
• With the help of a wireless bridge, we can connect the wireless networks with wireless segments.